(informal) An informal farewell

(idiomatic) Do not concern yourself with it; it is none of your business.

(idiomatic, informal) Used to positively assert the frank honesty of an associated statement of set of statements; equivalent to "to you tell the truth".

(idiomatic) Used to wish someone luck with a difficult endeavor.

(idiomatic) A phrase used to get someone's attention before announcing something.

Alternative form of back at you

Used to introduce one's opinion, without being asked for it.

(Britain) The national system whereby income tax and national insurance is deducted by an employer from the salary or wages of an employee.

goodbye; something said at a farewell, not necessarily literally meaning that the speaker will see the hearer(s) again.

Short for May God bless you; said as a short prayer for the recipient. / Said to somebody who has sneezed, as a rhetorical response. (see also bless you)